libsamplerate: A Sample Rate Converter library for audio1

Libsamplerate is a Sample Rate Converter for audio. One example of where
such a thing would be useful is converting audio from the CD sample rate
of 44.1kHz to the 48kHz sample rate used by DAT players.

Libsamplerate is capable of arbitrary and time varying conversions; from
downsampling by a factor of 12 to upsampling by the same factor. Arbitrary
in this case means that the ratio of input and output sample rates can be
an irrational number. The conversion ratio can also vary with time for
speeding up and slowing down effects.

Libsamplerate provides a small set of converters to allow quality to be
traded off against computation cost. The current best converter provides
a signal-to-noise ratio of 97dB with -3dB passband extending from DC to
96% of the theoretical best bandwidth for a given pair of input and
output sample rates.